• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.1 no.1
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• pp.1-9
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• 1997

We investigated the depth profiles of heavy metals in the surface sediments at Heedong reservoir in Pusan. Sampling was done at the intervals of 50 m of drift along the water channel into the reservoir. All samples were analyzed with an ICP-AES. We determined the content of Zn, Pb, Cd, Mn, Cu, Cr, and Fe. The overall mean content of these heavy metals were observed to $(2.9\pm1.2){\times}10^{-3},\;(1.3\pm0.7){\times}10^{-3},$ $(1.9\pm2.1){\times}10^{-4},$ $(2.3\pm1.1){\times}10^{-2},\;(1.6\pm1.0){\times}10^{-3},\;and\;(4.5\pm2.6){\times}10^{-4}$ ppm/ppmFe, respectively excluding iron data. Mean contents of Cu show an increasing trend toward the surface of sediments, while those of Cd show a decreasing trend, and those of Pb and Cr are relatively stable. Comparing with the contents of heavy metals in soils at two sites of Kumjeong mountain, enrichment factors of heavy metals in the surface sediments were determined. Among heavy metals we investigated, copper showed the largest value of enrichment factor. Considering the maximum content of heavy metals in the surface sediment, the values of enrichment factors of Cu, Cd and Cr were significant, which were 22, 8.1 and 4.0, respectively. In leaching experiment, it appeared that Pb, Cd, Cr, and Fe in sediments were hardly leached out into water, We also examined the effect of pH on the content of heavy metals.

• Journal of Environmental Science International
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• v.1 no.1
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• pp.1.2-9
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• 1992

We investigated the depth profiles of heavy metals in the surface sediments at Haedong reservoir in Pusan. Sampling was done at the intervals of 50 m of drift along the water channel into the reservoir. All samples were analyzed with an ICP-AES. We determined the content of Zn, Pb, Cd, Mn, Cu, Cr, and Fe. The overall mean content of these heavy metals were observed to $(2.9{\pm}1.2){\times}10^{-3}$, $(1.3{\pm}0.7){\times}10^{-3}$, $(1.9{\pm}2.1){\times}10^{-4}$ $(2.3{\pm}1.1){\times}10^{-2}$ $(1.6{\pm}1.0){\times}10{-3}$, and $(4.5{\pm}2.6){\times}10^{-4}$ ppm/ppm Fe, recpectively excluding iron data. Mean contents of Cu show an increasing trend toward the surface of sediments, while those of U show a decreasing trend, and those of Pb and Cr are relatively stable. Comparing with the contents of heavy metals in soils at two sites of Kumjeong mountain, enrichment factors of heavy metals in the surface sediments were determined. Among heavy metals we investigated, copper showed the largest value of enrichment factor. Considering the maximum content of heavy metals in the surface sediment, the values of enrichment factors of Cu, Cd and Cr were significant which were n, 8.1 and 4.0, respectively. In leaching experiment, it appeared that Pb, Cd, Cr, and Fe in sediments were hardly leached out into water. We also examined the effect of pH on the content of heavy metals.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4D
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• pp.561-567
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• 2008

In this study, shoreline change was analyzed by RTK-GPS and advanced airborne LiDAR survey. For extraction of coastline, first of all, tide correction was conducted at all RTK-GPS points through the comparing with the corresponding tidal height, and cross section providing coastline was produced using Autocad Civil3D program. Comparing with two results of RTK-GPS (first, 29 Aug 2007; second, 6 Oct 2007) surveys, coastline of the first result had been decreased about 21m compare with that of the second. And it was also demonstrated that the length of coastline by the first RTK-GPS was 15m shorter than that by the airborne LiDAR survey (Dec. 2006). In addition, we recoquized that the erosion appeared in the top right-hand (dock area); the sediment in the bottom left-hand (Chosun beach area) of the Haeundae beach. As a result, therefore, it was learned that artificial sand filling for beach open and natural effects such as a typhoon, current drift, wind direction gave cause for area changes and coastline.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.3
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• pp.179-187
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• 1977

This study intended to investigate the shape of the artificial fish reefs settled in the waters of Seogwipo, and the thronging of fish schools into them. The results obtained are summarized as follows : 1. Two types of artifical fish reef, circularized vertical type which is composed of Cryptomeria branches and parachute type, were put off the coast of Seogwipo at $33^{\circ}14'05'$ N Lat., $126^{\circ}34'40'$ E Long. The setting place is located 0.4 sea-mile away from natural fish reefs, at 25 m in depth. And its sediment is consisted of f. S. and Sh. 2. Maximum velocity of wind drift current was 15.28 cm/sec at 15 m depth. The Current direction was $20.5\%$n in the WSW. 3. Maximum fluid resistance of the circularized vertical type to current and wind waves showed about 890 kg, and the weight of sand bags attached to the fish reef totaling 1,200 kg was enough to sustain fish reef. 4. As maximum fluid resistance of the parachute type to current and wind waves was 106.3 kg, the retaining force of sand bags was enough to sustain the fish reef, but vinyl canvas and expansion materials were so poor that the fish reef was lost by the sea current and wind waves. 5. Sixteen species of fish among 53 usually caught in this area were thronged into the artificial fish reef. The fish catches comprized Porgy (Pagrosomus major) $23\%$, black kook fish (Sebastes (Mebarus) intermis) $13\%$, sand borer (Sillago sihama) $11\%$, Sebastes (Pteropodus) hubbsi $7\%$, and file fish (Monacanthus cirrhifer) $6\%$. According to the submarine observations by fivers, it was confirmed that a lot of fish larvae thronged in the middle part of the fish reefs.

• Journal of the Korean earth science society
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• v.44 no.6
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• pp.643-654
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• 2023

The West Philippine Basin, an oceanic basin half the size of the Philippine Sea Plate, lies in the western part of the plate and south of the Korean Peninsula on the Eurasian Plate. It subducts beneath the Eurasian Plate and the Philippine Islands bordering the Ryukyu Trench and the Philippine Trench with 25-50% of this basin already consumed. However, the history of the opening of the basin's southern region has been a topic of debate. The non-transform discontinuity formed during the seafloor spreading is similar to the transform fault boundaries normally perpendicular to mid-ocean ridge axes; however, it was created irregularly due to ridge propagations caused by variations of mantle convection attributable to magma supply changes. By analyzing high-resolution multi-beam echo-sounding data, we confirmed that the non-transform discontinuity due to the propagating rift evolved in the entire basin and that the abyssal hill strike direction changed from E-W to NNW-SSE from the fossil spreading center. In the early stage of basin extension, the Amami-Sankaku Basin was rotated 90 degrees clockwise from its current orientation, and it bordered the Palau Basin along the Mindanao Fracture Zone. The Amami-Sankaku Basin separated from the Palau Basin while the spreading of the West Philippine Basin began with a counter-clockwise rotation. This indicates that the non-transform discontinuities formed by a sudden change in magma supply due to the drift of the Philippine Sea Plate and simultaneously with the rapid changes in the spreading direction from ENE-WSW to N-S. The Palau Basin was considered to be the sub-south of the West Philippine Basin, but recent studies have shown that it extends into an independent system. Evidence from sediment layers and crustal thickness hints at the possibility of its existence before the West Philippine Basin opened, although its evolution continues to be debated. We performed a combined analysis using high-resolution multi-beam bathymetry and satellite gravity data to uncover new insights into the evolution of the West Philippine Basin. This information illuminates the complex plate interactions and provides a crucial contribution toward understanding the opening history of the basin and the Philippine Sea Plate.